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Structure

The structure of AbstractDomain is given below.

TYPE, ABSTRACT :: AbstractDomain_
  PRIVATE
  LOGICAL(LGT) :: isInitiated = .FALSE.
    !! flag
  TYPE(String) :: engine
    !! Engine used for generating the meshes
  INTEGER(I4B) :: majorVersion = 0
    !! Major version
  INTEGER(I4B) :: minorVersion = 0
    !! Minor version
  REAL(DFP) :: version = 0.0_DFP
    !! Version  MajorVersion.MinorVersion
  INTEGER(I4B) :: nsd = 0_I4B
    !! number of spatial dimension
  INTEGER(I4B) :: maxNptrs = 0
    !! Largest node number in the domain
  INTEGER(I4B) :: minNptrs = 0
    !! Smallest node number in the domain
  INTEGER(I4B) :: tNodes = 0
    !! Total number of nodes in the mesh
  LOGICAL(I4B) :: isNodeNumberSparse = .FALSE.
    !! True if node numbers are not continuous
  INTEGER(I4B) :: maxElemNum = 0
    !! Largest element number in the domain
  INTEGER(I4B) :: minElemNum = 0
    !! Smallest element number in the domain
  LOGICAL(LGT) :: isElemNumberSparse = .FALSE.
    !! True if element numbers are sparse
  INTEGER(I4B) :: tEntitiesForNodes = 0
    !! Total number of entities required for reading nodes
  INTEGER(I4B) :: tEntitiesForElements = 0
    !! Total number of entities required for reading elements
  INTEGER(I4B) :: tElements(0:3) = [0, 0, 0, 0]
    !! Total number of elements inside the domain
    !! tElements( 0 ) = total number of point elements
    !! tElements( 1 ) = total number of line elements
    !! tElements( 2 ) =  total number of surface elements
    !! tElements( 3 ) = total number of volume/cell elements
  INTEGER(I4B) :: tEntities(0:3) = [0, 0, 0, 0]
    !! Total number of entities inside the domain
    !! tEntities( 0 ) = total number of point mesh entities, mesh of Points
    !! tEntities( 1 ) = total number of line mesh entities, mesh of Edge
    !! tEntities( 2 ) = total number of surface mesh entities, mesh Boundary
    !! tEntities( 3 ) = total number of volume mesh entities, Omega
  REAL(DFP), ALLOCATABLE :: nodeCoord(:, :)
    !! Nodal coordinates in XiJ format
    !! Number of rows are 3, and number of columns is total nodes

  CLASS(AbstractMesh_), POINTER :: meshVolume => NULL()
    !! meshVolume list of meshes of volume entities
  CLASS(AbstractMesh_), POINTER :: meshSurface => NULL()
    !! meshSurface list of meshes of surface entities
  CLASS(AbstractMesh_), POINTER :: meshCurve => NULL()
    !! meshCurve list of meshes of curve entities
  CLASS(AbstractMesh_), POINTER :: meshPoint => NULL()
    !! meshPoint list of meshes of point entities

  TYPE(CSRSparsity_) :: meshMap
  !! Sparse mesh data in CSR format

END TYPE AbstractDomain_

What is the difference between domain and mesh​

A mesh is a collection of same topological order, that is,

  • a mesh of volume elements
  • a mesh of surface elements
  • a mesh of curve elements
  • a mesh of point elements

The element number and the node number in the mesh can be sparse. Therefore, we need to create a mapping from local numbering to global numbering. The mesh data does not contain any node coordinate information. The node coordinate data is available in Domain. It is stored inside nodeCoord array in xij format. We need global node number to access the entries in nodeCoord. These global node numbers are stored inside the mesh.